The present invention broadly relates to an industrial truck or vehicle and, more specifically, pertains to a new and improved construction of an industrial truck or transport vehicle with an integrated emergency recovering device.
Generally speaking, the industrial truck or transport vehicle of the present invention has an integrated emergency recovery device and is especially designed for automatic steering or guidance along a guide line or path. This industrial truck or vehicle with an integrated emergency recovery device comprises a support body or member containing an elevatable platform. Each end of this support body or member is supported and guided by a respective driving module or unit. Each respective drive unit possesses a steerable and brakeable drive wheel and self-steering, free-running support or caster or follower wheels which trail or are subsequent to the associated drive wheel as seen in an appropriate direction of vehicle travel. The industrial truck or vehicle furthermore contains devices for receiving, processing and transmitting signals relative to a stationary device which transmits and receives these signals along the travel path or surface for controlling the industrial truck or transport vehicle.
In other words, the industrial truck or transport vehicle of the present invention is preferably for automatically following a guide line or path and comprises a support body. The support body has a first end and has a second end and is provided with an elevatable platform. The industrial truck or transport vehicle also comprises a first drive module for supporting and guiding the support body at the first end as well as a second drive module for supporting and guiding the support body at the second end. Each drive module of the first drive module and the second drive module has at least one steerable and brakeable drive wheel and at least two self-steering follower or support wheels.
Such industrial trucks or vehicles are generally employed for the integration of automatic transportation and warehousing technology in flexible production and assembly systems, for example during the assembly of units in the automobile and electronic industries and during the production of a broad range of products.
An industrial truck or vehicle, in particular a lateral lifting truck or vehicle with an elevatable load carrier, is known from the German Patent Publication No. 2,144,786, published Mar. 15, 1973, for traveling in the aisles between shelves or partitions and for depositing or stacking and removing or unstacking articles, goods or wares. This industrial truck or vehicle comprises two individual vehicle portions or modules connected by means of an elevatable load carrier. Each of these individual vehicle portions or modules possesses a guide mast. One of these individual vehicle portions or modules comprises a drive motor and an operator location or area. A special or supplementary transverse connection between both individual vehicle portions or modules is thus not necessary. The connection between the elevatable load carrier and the guide masts is accomplished by means of rollers which lie with their axes approximately transverse to a connecting line between the individual vehicle portions or modules and corresponding rails. Lateral stops or stop limits are provided for the load carrier. Appropriate double roller and center rails are used for connection between the guide masts and the load carrier to permit minimum possible play between the individual vehicle portions. The load carrier is constructed in a telescopic manner, wherein each telescoping part is particularly constructed and associated as a connecting member.
Even though with the aforesaid construction of the industrial truck or vehicle no tipping moment results from the load in the direction of travel, this industrial truck or vehicle nevertheless has the disadvantage that when encountering uneven or irregular travel paths the travel surface adhesion or floor traction of at least one of the drive wheels can be diminished, especially of the steerable drive wheel. The freedom of motion in the vertical direction existing between both individual vehicle portions or modules of the industrial truck or vehicle for overcoming unlevel or uneven sections of the floor or travel surface is structurally complex and tends to jam in consequence of uneven wearing of the drive wheels and of the free-running support wheels, or because of surface irregularities, especially skewed irregularities, in particular with a fully extended load carrier.
Furthermore, both individual vehicle portions of the industrial truck or vehicle are solely connected by means of the elevatable load carrier. Thus, there is no possibility of harmonizing the frame construction of fabrication of the industrial truck or vehicle such that, on the one hand, the frame construction is sufficiently rigid or inflexible with respect to the desired tilting stability and, on the other hand, is elastically deformable to the extent that all rollers and wheels are provided with constant contact with the floor or travel surface.
It has also proven disadvantageous that the aforementioned industrial truck or vehicle does not possess an integrated emergency recovery device. Thus, if this industrial truck or vehicle incurs a blocked drive wheel, it can only be removed from the aisles between the shelves or partitions with the assistance of an emergency recovery vehicle especially provided therefor. The use of this industrial truck or vehicle is accordingly limited to those applications in which the unhindered access of an emergency recovery vehicle is continuously guaranteed. Most applications in flexible assembly plants and production systems are thus precluded, since for architectural or constructional reasons an emergency recovery device or vehicle cannot be brought into these areas to the industrial truck or vehicle quickly enough or indeed at all. For this reason, complete autonomy of the industrial truck or vehicle is required with respect to emergency recovery.